Field of the Invention
The present invention relates to an annular spring that transmits a rotational drive force that is transmitted to one of an inner circumferential section and an outer circumferential section to the other one, and a torque detecting device and a robot joint mechanism using the annular spring.
Description of the Related Art
There has been conventionally known a robot comprising a base body as a trunk, a head section that is provided on an upper portion of the base body, left and right arm bodies that are provided extendedly from both left and right sides of the upper portion of the base body, hand sections that are provided at tip end portions of the arm bodies, left and right leg bodies that are extendedly provided downward from a lower portion of the base body, and foot sections that are attached to tip end portions of the leg bodies, similarly to a human being. A robot of this kind can perform bending and stretching movements of the arm bodies and the leg bodies in a plurality of joint mechanisms corresponding to joints such as shoulder joints, elbow joins, wrist joints, hip joints, knee joints, and ankle joints of a human being.
As the joint mechanism which is used to enable the bending and stretching movements as above, there is a joint mechanism comprising a drive source such as an actuator, an annular spring to which a drive force is transmitted from a reduction mechanism, and a link mechanism that has the drive force transmitted from the annular spring and causes the respective sections of a robot to perform bending and stretching movements.
As the annular spring, there is an annular spring that has an annular outer circumferential section, an annular inner circumferential section that is disposed on an inner circumferential side of the outer circumferential section, and an elastic section that is disposed between the outer circumferential section and the inner circumferential section. As the elastic section of the annular spring like this, there are an elastic section that is in a cantilever shape where bending stress is generated when the outer circumferential section and the inner circumferential section relatively rotate and a load is applied thereto, and an elastic section that is in a shape of a torsion bar where torsional stress is generated, (refer to Japanese Patent No. 4801534, for example).
In the joint mechanisms which are configured as above, the elastic sections of the annular springs absorb impacts at the time of the arm bodies and leg bodies to be bent and stretched contacting or colliding with obstacles or the like, and thereby protect the joint mechanisms. Further, in the joint mechanisms as above, deformation degrees of components of the annular springs are measured, and the rotational drive forces (torque) which are transmitted are calculated based on the detection values.